Emergency line operators always stay calm and make sure that they get all the information they need to send help.
A. can
B. would
C. must
D. might
网友回答
A. can
B. would
(答案→)C. must
D. might
解析：can能，会；would将，意愿；must必须；might也许。句意：报警电话的接线员必须保持镇静并且确保他们得到的需要帮助的有关信息发出去。根据句意应选C。